Method for Transverse Rolling

ABSTRACT

The present invention relates to a cross rolling method having the step of shaping a component blank rotating about a main axis of rotation by means of at least two cross rolling tools located substantially opposite each other with respect to the component blank for the production of a component ( 1, 2 ) that is at least partly non-rotationally symmetrical and non-cyclically symmetrical with respect to the main axis of rotation, by moving the cross rolling tools along their main direction of movement. The invention also relates to a cross rolling tool for producing an at least partly non-rotationally symmetrical and non-cyclically symmetrical component ( 1, 2 ). Likewise, the present invention relates to an apparatus for carrying out the method according to the invention and a component ( 1, 2 ) produced in accordance with the method according to the invention.

The present invention relates to a cross rolling method and an apparatus for carrying out the method, a component produced in accordance with the method and a cross rolling tool.

Cross rolling methods are sufficiently well-known from the prior art. During cross rolling, shaping of a rotationally symmetrical blank takes place between two cross rolling tools. Here, a distinction is to be drawn between round cross rolling and flat die cross rolling.

In round cross rolling, the blank or the rolling material rotates about its own axis between two tool rolls rotating in the same direction. Here, shaping is generally carried out by feeding in at least one tool roll and on the basis of the geometries of the rolling tool surface. By means of the known round cross rolling methods, stepped, rotationally symmetrical workpieces or corresponding pre-forms can be produced with optimal mass distribution.

In flat die cross rolling, the blank or the rolling material is shaped between two tool plates running horizontally or vertically and translationally with respect to each other. As opposed to the round cross rolling tools of the round cross rolling method, the tools of flat die cross rolling are distinguished by a substantially flat geometry.

The cross rolling methods are distinguished, amongst other things, by the achievement of high shape and dimensional accuracies of the workpieces, a comparatively higher sequence of items as compared with removal processes, high material utilization and high-volume throughput, low impairment of the workpiece structure, high tool service lives and low tool and fabrication costs. Cross rolling methods thus constitute an economically particularly interesting method for shaping in particular elongated components.

Previous cross rolling methods were, however, restricted to the production of rotationally symmetrical workpieces.

It is thus an object of the present invention to widen the area of application of a cross rolling method.

This object is achieved by the subject matter of the independent claims. The dependent claims develop the central idea of the invention in a particularly advantageous way.

According to a first aspect, the present invention relates to a cross rolling method which is distinguished by the step of shaping a component blank rotating about a main axis of rotation by means of at least two cross rolling tools located substantially opposite each other with respect to the component blank; and specifically to the production of a component that is at least partly non-rotationally symmetrical and non-cyclically symmetrical with respect to the main axis of rotation, by moving the cross rolling tools along their main direction of movement.

“At least partly” is to be understood to mean that only individual circumferential areas or sections of the component (blank), viewed along the main axis of rotation, are non-rotationally symmetrically and non-cyclically symmetrically shaped, viewed along the main axis of rotation; or else the entire component. In the first-named case, the other areas/sections of the component (blank) can even not be shaped or, to achieve a rotationally symmetrical contour of the component, for example, shaped with respect to its main axis of rotation.

“Non-rotationally symmetrical and non-cyclically symmetrical” is to be understood to mean every asymmetric configuration of the component, for example in its cross section (at least—viewed axially—in subareas of the component; cf., for example, FIG. 3) or with respect to its overall geometric configuration (cf., for example, FIG. 2), in particular with reference to its main axis of rotation or its “main axis of symmetry”. For instance, an eccentric-like (for example displacement of the mass center of gravity out of the main axis of rotation or “main axis of symmetry”) and/or non-round (for example egg-shaped) formation at least—viewed axially—of subareas of the component are conceivable here, the application not being restricted hereto.

The main direction of movement of the cross rolling tools can be a rotational or translational main direction of movement. A combination of these is also conceivable, wherein then at least one proportion of the translational main direction of movement can, for example, represent a translational feeding movement of the cross rolling tool with respect to (i.e., for example, at right angles to) the main axis of rotation of the component blank.

The cross rolling method according to the invention can be any desired cross rolling method; i.e., for example, a round cross rolling method or a flat die cross rolling method. Consequently, the cross rolling method according to the invention can be applied to all known cross rolling methods. Even if previously the option of a translational direction of movement of the cross rolling tools in the course of a feeding movement of the same with respect to the main axis of rotation of the component blank was represented as a possible option, then the component blank is preferably (solely) shaped by the tool geometry of the cross rolling tools. In this way, the construction of a corresponding apparatus can also be designed in a simplified manner.

The cross rolling tools can be two tool rolls preferably rotating in the same direction with a rotational main direction of movement about their axis of rotation, or two tool plates running translationally with respect to each other with their translational main direction of movement in the plane of their extent. In principle, more than two corresponding cross rolling tools are also conceivable, although this is not always desired for reasons of space. When the cross rolling method is carried out by means of tool rolls, a method corresponding to a round cross rolling method is preferably carried out; when tool plates are used for the cross rolling method, a method corresponding to a flat die cross rolling method is preferably carried out.

Within the context of the invention, “plane of their extent” is understood to mean the plane of the preferably flat cross rolling tool (tool plate) extending parallel to the main direction of movement and preferably also parallel to the main axis of rotation of the component, for example for one type of flat die cross rolling method.

The axes of rotation of the tool rolls and the translational main directions of movement of the tool plates or the planes of their extent are preferably oriented parallel to one another, in order thus preferably to lie opposite each other during the cross rolling method and thus to effect the most effective shaping possible, since the component is then provided/clamped in centrally between the tools.

At least in the areas in which the component is intended to be formed non-rotationally symmetrically and non-cyclically symmetrically, the cross rolling tools have a surface contour which is complex and preferably resulting from the application of material flow FEM (finite element methods). This surface contour is given on the basis of the desired final contour of the component blank, the tools to be used, the type of cross rolling method, the dimensions both of the component blank, on the one hand, and also of the cross rolling tools, on the other hand, and/or the materials used, this enumeration not being final.

Here, for example, viewed over their circumference, at least in the areas viewed in the axial direction with respect to their axis of rotation in which the component is to be formed non-rotationally symmetrically and non-cyclically symmetrically, the surfaces of the cross rolling tools can have a non-constant spacing from the axis of rotation. With reference to previous embodiments, this applies in particular to the tool rolls of a round cross rolling method.

A “non-constant spacing from the axis of rotation” within the context of the invention means that, in the corresponding areas of the cross rolling tool with which the corresponding parts/sections of the component blank are to be shaped in a non-rotationally symmetrical and non-cyclically symmetrical way, are formed non-rotationally symmetrically with respect to the axis of rotation of the tool. Instead, in the corresponding areas/sections, the cross rolling tool has a changing radius, viewed over the circumference, which can change in any desired way in accordance with the desired final geometry of the component, viewed over the circumference; that is to say, for example, abruptly, smoothly, linearly, non-linearly, in combinations thereof and in other desired ways.

Furthermore, viewed along the plane of their extent, at least in the areas along the translational main direction of movement in which the component is intended to be non-rotationally symmetrically and non-cyclically symmetrically formed, the surfaces of the cross rolling tools can have a non-constant spacing from the plane of extent. This applies in particular to the tool plates of a flat die cross rolling method.

Within the scope of the invention, a “non-constant spacing from the plane of extent” is understood to mean that, in a way similar to the “non-constant spacing from the axis of rotation” of the previously described tool rolls, the spacing of the currently effective surface of the cross rolling tool from the main axis of rotation of the component blank varies along the main direction of movement and, likewise, for example along the main direction of movement, can change abruptly, smoothly, linearly, non-linearly, constantly, non-constantly, in combinations thereof and in any other desired way.

In a preferred refinement—relating to the geometry—, the surface areas of a cross rolling tool that are effective for the shaping can always lie accurately opposite the same surface areas of the component blank that are to be shaped.

From a process technology point of view, the rolling operations between component blank and cross rolling tools are preferably coordinated with one another in such a way that, as viewed over the circumference of the component blank, the same (at least relating to the geometry; i.e. geometric or geometrically identical) areas of the cross rolling tools are always assigned to the same areas of the component blank. For example, in round cross rolling, the cross rolling tool preferably rotates exactly once through 360° about its axis of rotation for the processing of a workpiece, wherein the workpiece rotates at least likewise once or preferably also many times about its main axis of rotation.

“Relating at least to the geometry” means that it does not actually have to be the identical areas of the cross rolling tool which are assigned to the same areas of the component blank. In principle, it is also conceivable that geometrically identical areas are respectively always assigned to the same areas of the component blank; this, for example, during a periodic repetition of corresponding surface contours. It is also conceivable that the cross rolling tools are formed in such a way that it is just always other areas of the cross rolling tool, which, preferably during a movement sequence, as viewed in a direction of the main direction of movement, are brought into effective contact with the component blank for the purpose of the shaping, that come into contact with the same areas of the component blank, in order thus for example to permit continuous shaping—that is to say stepwise shaping of the respective areas.

According to a preferred refinement of the present invention, at least in the surface areas in which the component is intended to be formed non-rotationally symmetrically and non-cyclically symmetrically, as viewed along its surface in the main direction of movement, one of the cross rolling tools can have at least one subarea with a contour through which material is forced at right angles to the main axis of rotation of the component blank (preferably in the radial direction as viewed towards the main axis of rotation)—that is to say preferably radially. The substantially opposite cross rolling tool can have a corresponding contour assigned to the subarea of the one cross rolling tool and preferably located opposite in a subarea, in order to accommodate the material forced at right angles to the main axis of rotation of the component blank in the corresponding contour. In this way, for example, the center of gravity of the relevant part/section of the component blank or component can also be displaced out of the main axis of rotation by means of a cross rolling method.

Alternatively or additionally, at least in the surface areas in which the component is to be formed non-rotationally symmetrically and non-cyclically symmetrically, preferably one of the cross rolling tools, as viewed along its surface in the main direction of movement, can have at least one subarea with a contour in order to force material at right angles to the main axis of rotation of the component blank—i.e. preferably radially, wherein the substantially opposite cross rolling tool has a contour assigned to the subarea of the one cross rolling tool and preferably located opposite in a subarea, in order in the same way to force material at right angles to the main axis of rotation of the component blank—i.e. preferably radially. In this way, the material of the component blank is forced from two opposite sides toward each other, in order, in this circumferential and axially preferably limited subarea of the cross rolling tools, to achieve a non-round shape of the component, for example.

A cross rolling tool can also have more than one of the aforementioned subareas. The number and (axial) width of the same are not limited. Of course, any desired number of different subareas, as previously described, can also be provided. In addition, the subarea can extend axially or in its width over the entire cross rolling tool; at least in the active area of the cross rolling tool.

The contour(s) can form elevations and/or cavities with respect to the central surface spacing of the cross rolling tools with respect to the main axis of rotation of the component blank. Expressed in simplified or generalized terms, the contour preferably has elevations and/or cavities as geometry or geometries in the tool surface.

The contour(s) can have periodically repeating geometries over the rolling length of the cross rolling tool. In particular, defined elevations and/or cavities can therefore extend periodically (repeatedly) over the rolling length of the cross rolling tool.

According to a further aspect, the present invention likewise relates to a cross rolling tool for producing an at least partly non-rotationally symmetrical and non-cyclically symmetrical component. Some refinements of such a cross rolling tool have already previously been described. To this extent, reference is also made to the entire extent of the preceding explanations.

At least in the areas in which the component is to be formed non-rotationally symmetrically and non-cyclically, the cross rolling tool can have a complex surface contour, preferably resulting from the application of material flow FEM.

At least in the areas, viewed in the axial direction with respect to an axis of rotation of the cross rolling tool, in which the component is to be formed non-rotationally symmetrically and non-cyclically symmetrically, the surface of the cross rolling tool, viewed over its circumference, can have a non-constant spacing from the axis of rotation of the cross rolling tool. With respect to this feature, reference is also made to the above explanation.

According to an alternative refinement, viewed along a plane of extent of the cross rolling tool, at least in the areas along a translational main direction of movement of the cross rolling tool in which the component is to be shaped non-rotationally symmetrically and non-cyclically symmetrically, the surface of the cross rolling tool can have a non-constant spacing from the plane of extent. With respect to this feature, reference is also made to the above explanations.

At least in the surface areas in which the component is to be formed non-rotationally symmetrically and non-cyclically symmetrically, as viewed along its surface in the main direction of movement, the cross rolling tool can preferably have at least one subarea with a contour by which material can be forced away from the cross rolling tool or can be accommodated in the contour. The contour can have elevations and/or cavities as geometry or geometries in the tool surface. The contour can also have periodically repeating geometries over the rolling length of the cross rolling tool. It is also conceivable for elevations and/or cavities to be formed periodically (repeatedly) over the rolling length of the cross rolling tool. The repeating geometries can differ slightly from one another during each revolution of the component (blank), in such a way that they effect stepwise shaping of the component (blank).

According to a further aspect, the present invention relates to an apparatus for carrying out the method according to the invention, wherein the apparatus preferably uses a cross rolling tool according to the present invention.

According to a further aspect, the present invention also relates to a component produced in accordance with the method according to the invention.

In the figures described below, two possible component geometries which can be produced by the novel cross rolling method are illustrated by way of example. In the figures:

FIG. 1 shows, schematically, a component produced by a conventional cross rolling method in a simplified illustration, only one (upper) side with respect to the axis of rotation of the rotationally symmetrical component being illustrated,

FIG. 2 shows, schematically, a component according to the invention according to a first exemplary embodiment of the invention, and

FIG. 3 shows, schematically, a component according to the invention according to a second exemplary embodiment of the invention in two illustrations which are not true to scale in relation to each other.

The component 10 illustrated in FIG. 1 represents a component 10 produced by means of a conventional cross rolling method, which is formed rotationally symmetrically with respect to its axis of rotation R₁₀ (only one (upper) side with respect to the axis of rotation R₁₀ of the component 10 is illustrated).

In FIG. 2, in simplified form, a component 1 according to the invention according to a first exemplary embodiment of the invention is illustrated. In the areas A and C illustrated with respect to the longitudinal or main axis of rotation R₁ of the component 1, the component 1 has been shaped in a conventional way and, in these areas A, C, is formed rotationally symmetrically. However, in the central area B, the component 1 according to the invention has been shaped correspondingly in such a way that this area B is formed non-rotationally symmetrically and non-cyclically symmetrically with respect to the main axis of rotation R₁ of the component 1. In particular, in the area B the axis (of symmetry) R_(B) of this region B has been moved away or offset out of the main axis of rotation R₁ of the component 1, and thus the mass center of gravity in the area B is arranged to be displaced downward from the main axis of rotation R₁ in FIG. 2. The configuration according to FIG. 2 may be used, for example, in the area of crankshafts.

The component 1 illustrated in FIG. 2 has been produced by a method according to the invention with tools according to the invention, as described above; for example, by providing mutually opposite cavities (tool at the bottom) and elevations (tool at the top), so that, with appropriately oppositely acting tools, the material is forced and flows into the lower area of the component 1 shown in FIG. 2.

FIG. 3 shows a further component 2 according to the invention according to a second exemplary embodiment of the present invention. As illustrated in FIG. 3a , this component 2 also has areas A, C which are symmetrical with respect to its longitudinal or main axis of rotation R₂, which are formed rotationally symmetrically in particular with respect to the main axis of rotation R₂. Likewise, the component 2 according to FIG. 3 also has an area B which is non-rotationally symmetrical and non-cyclically symmetrical with respect to the main axis of rotation R₂. In this area B, not only is the mass center of gravity displaced with respect to the main axis of rotation R₂ (upward here). In addition, the geometry of the component 2 in this area B is non-round (egg-shaped here, for example), as is illustrated in FIG. 3b , which shows a section—not true to scale—through the component 2 in FIG. 3a . Such a configuration can be used, for example, in the area of camshafts.

The component 2 illustrated in FIG. 3 has also been produced by a method according to the invention with tools according to the invention, as described above. Here, the areas O, U bulged upward and downward in FIG. 3b of the “egg-shaped” cross-sectional geometry have been produced, for example, by providing mutually opposite cavity (tool at the top) and elevation (tool at the bottom) in the appropriate revolving partial sections of the tools or tool surfaces, so that, with appropriately oppositely acting tools, the material is forced and flows into the upper area O of the component 1 shown in FIG. 3b . The left and right areas L, R of the “egg-shaped” cross-sectional geometry in FIG. 3b have been produced, for example, by providing mutually opposite elevations in the corresponding revolving partial sections of the tools or tools surfaces, so that, with appropriately oppositely acting tools, the material is forced and flows towards each other in the lateral areas L, R of the component 1 shown in FIG. 3 b.

It should be noted that the exemplary configurations illustrated in FIGS. 2 and 3 of components 1, 2 according to the invention are of course not restrictive, and any combination of any desired configurations of corresponding components which have at least one at least partly non-rotationally symmetrical and non-cyclically symmetrical geometry with respect to the main axis of rotation R₁, R₂ is conceivable.

The invention is consequently not restricted to the present exemplary embodiments if it is supported by the subject matter of the following claims. 

1. Cross rolling method having the step of shaping a component blank rotating about a main axis of rotation by means of at least two cross rolling tools located substantially opposite each other with respect to the component blank for the production of a component (1, 2) that is at least partly non-rotationally symmetrical and non-cyclically symmetrical with respect to the main axis of rotation, by moving the cross rolling tools along their main direction of movement.
 2. Cross rolling method according to claim 1, wherein the main direction of movement is a rotational or translational main direction of movement.
 3. Cross rolling method according to claim 1, wherein the cross rolling method is a round cross rolling method or a flat die cross rolling method.
 4. Cross rolling method according to claim 1, wherein the component blank is shaped by the tool geometry of the cross rolling tools.
 5. Cross rolling method according to claim 1, wherein the cross rolling tools are two tool rolls preferably rotating in the same direction with a rotational main direction of movement about their axis of rotation, or two tool plates running translationally with respect to each other with their translational main direction of movement in the plane of their extent.
 6. Cross rolling method according to claim 5, wherein the axes of rotation of the tool rolls and the translational main directions of movement of the tool plates are oriented parallel to one another.
 7. Cross rolling method according to claim 1, wherein, at least in the areas in which the component (1, 2) is intended to be formed non-rotationally symmetrically and non-cyclically symmetrically, the cross rolling tools have a surface contour which is complex and preferably resulting from the application of material flow FEM (finite element methods).
 8. Cross rolling method according to claim 1, wherein, viewed over their circumference, at least in the areas viewed in the axial direction with respect to their axis of rotation in which the component (1, 2) is to be formed non-rotationally symmetrically and non-cyclically symmetrically, the surfaces of the cross rolling tools have a non-constant spacing from the axis of rotation.
 9. Cross rolling method according to claim 1, wherein, viewed along the plane of their extent, at least in the areas along the translational main direction of movement in which the component (1, 2) is intended to be non-rotationally symmetrically and non-cyclically symmetrically formed, the surfaces of the cross rolling tools have a non-constant spacing from the plane of extent.
 10. Cross rolling method according to claim 1, wherein the surface areas of a cross rolling tool that are effective for the shaping are always located accurately opposite the same surface areas of the component blank that are to be shaped.
 11. Cross rolling method according to claim 1, wherein the rolling operations between component blank and cross rolling tools are coordinated with one another in such a way that, as viewed over the circumference of the component blank, the same areas of the cross rolling tools are always assigned to the same areas of the component blank.
 12. Cross rolling method according to claim 1, wherein, at least in the surface areas in which the component (1, 2) is intended to be formed non-rotationally symmetrically and non-cyclically symmetrically, as viewed along its surface in the main direction of movement, one of the cross rolling tools has at least one subarea with a contour through which material is forced at right angles to the main axis of rotation of the component blank, preferably radially, wherein the opposite cross rolling tool has a corresponding contour assigned to the subarea of the one cross rolling tool and preferably located opposite in a subarea, in order to accommodate the material forced at right angles to the main axis of rotation of the component blank in the corresponding contour.
 13. Cross rolling method according to claim 1, wherein, at least in the surface areas in which the component (1, 2) is to be formed non-rotationally symmetrically and non-cyclically symmetrically, one of the cross rolling tools, as viewed along its surface in the main direction of movement, has at least one subarea with a contour in order to force material at right angles to the main axis of rotation of the component blank, preferably radially, wherein the opposite cross rolling tool has a contour assigned to the subarea of the one cross rolling tool and preferably located opposite in a subarea, in order in the same way to force material at right angles to the main axis of rotation of the component blank, preferably radially.
 14. Cross rolling method according to claim 12, wherein the contour has elevations and/or cavities as geometry or geometries in the tool surface, wherein in particular the contour form elevations and/or cavities with respect to the central surface spacing of the cross rolling tools with respect to the main axis of rotation of the component blank.
 15. Cross rolling method according to claim 12, wherein the contour has periodically repeating geometries over the rolling length of the cross rolling tool. 16-25 (canceled) 